The present invention relates generally to agricultural combines. It relates particularly to rotary combines and, more particularly, to the rotor assembly in a rotary combine.
A well-known form of harvesting machine is a rotary combine. A typical combine includes a crop harvesting header assembly which reaps grain stalks and feeds the grain stalks to a rotary threshing assembly. The grain stalks or other crop materials harvested in the field are moved rearwardly from the crop harvesting header assembly by a crop feeder assembly and introduced for threshing to the rotary threshing and separating assembly.
In a rotary combine, the rotary threshing and separating assembly includes a generally tubular rotor housing mounted in the combine body. A driven rotor is coaxially mounted within the housing. The rotor comprises a frusto-conical infeed section and a cylindrical threshing and separating section, and is supported at opposite ends by front and rear bearings.
The cylindrical threshing and separating section of the rotor, and its surrounding rotor housing, mount cooperating threshing elements which thresh grain from other material in a threshing zone. The crop material is threshed and separated as it spirals around the rotor threshing section, and separated grain passes through openings in the surrounding rotor housing.
As discussed in Tanis, U.S. Pat. No. 5,387,153, and Tanis et al., U.S. patent application Ser. No. 09/412,468, assigned to the same assignee as the present invention, the ability to transfer crop materials from the feeder assembly to the threshing zone of the rotor assembly is critical to efficient combine operations. Most rotary combine rotors include an infeed section impeller comprised of a series of impeller blades arranged at a forward end of the rotor. The impeller blades rotate within a shroud which is a forward part of the rotor housing. During harvesting operations, the generally linear movement of the crop materials received from the feeder assembly is converted by the rotating impeller blades into a rotating, circulatory movement, in a rearward and outward direction.
In the Tanis et al. application, a new and improved impeller blade construction and arrangement is disclosed. The present application relates specifically to the construction and arrangement of the shroud which encloses the impeller. In that sense, the shroud of the present invention finds particularly advantageous application with the impeller disclosed in the aforementioned Tanis et al. application.
It is an object of the invention to provide a new and improved shroud for the infeed section impeller of the rotor in a rotary combine.
It is another object to provide a shroud whose geometry results in a crop delivery pattern which substantially eliminates localized areas of intensive crop pressure against the working surfaces of the rotor and rotor housing.
It is still another object to provide an infeed section shroud which enhances throughput capacity of the combine.
It is a further object to provide an infeed section shroud which controls crop flow in a manner which improves the energy efficiency of the rotor operation.
It is yet another object to provide an infeed section shroud which controls crop flow in a manner which improves component wear life.
The foregoing and other objects are realized in an infeed section shroud which combines a rear converging wall cone and a front diverging wall cone. The diverging wall cone or xe2x80x9creversexe2x80x9d cone diverges from a crop inlet opening at the front end of the shroud to its junction with the converging cone. The opposed cones or, more precisely, frustums of cones, enclose the impeller blades on the infeed section impeller of the rotor. The reverse cone is interrupted on one side by a transition member and a reverse transition member which, together, extend angularly around the axis of the impeller from about the 2:30 o""clock position, to about the 5:30 o""clock position as viewed from the front of the combine.
From the aforementioned (about) 5:30 o""clock position to about the 7:30 o""clock position the reverse cone continues and forms a sump behind a horizontal feed plate assembly of the shroud. From this 7:30 o""clock position to about the 9:00 o""clock position the reverse cone is again interrupted. At the 9:00 o""clock position the reverse cone is restored in the form of a reverse cone support member which supports and mounts a reverse cone rotor door extending over the top of the shroud to the aforementioned 2:30 o""clock position.
The rear, converging wall cone is mounted on a cylindrical housing member which mates with the cylindrical housing for the threshing rotor. The trailing edges of the impeller blades and the rear of the impeller itself extend into this cylindrical housing member. Arranged in helical paths extending circumferentially within the converging wall cone is a series of at least three crop directing vanes.
Similarly, arranged in helical paths extending circumferentially within the cylindrical housing member is another series of at least three crop directing vanes. The vanes extend radially inwardly to inner edges which are spaced only a short distance from the traces defined by the outer edges of the impeller blades as they rotate.
Crop material is fed into the shroud through a horizontal feed opening in the front face of the front diverging wall cone. A mat of crop material is fed up over an inlet ramp by the feed conveyor. This mat falls into the shroud""s sump where it is picked up by the rotating impeller blades and carried in a counter-clockwise direction (viewed from the front) onto the rear, converging wall cone. The vanes lead and separate the crop mat into three continuous rows of crop material which are moved rearwardly in helical patterns into the threshing section of the rotor assembly.